As fuel economy standards are being increased, reducing the weight of a vehicle while improving aerodynamics are key priorities for the automotive industry. To help improve aerodynamics, underbody shields are being added to the underside of vehicles. Although shielding can improve the aerodynamics, these underbody shields have the negative impact of adding weight to the vehicle. Many different approaches have been used to reduce the weight of paneling and underbody shields on vehicles. For example, many manufacturers use covers and shields made from low cost polymers such as polypropylene and high density polyethylene. To help improve the stiffness and heat resistance of these polymers, material fillers such as glass and talc are frequently added. These material blends have been chosen since they are affordable and use traditional components. These materials however, lack the properties of sound attenuation and heat deflection required in vehicles.
Another approach used by manufacturers to reduce the weight while addressing the NVH and aerodynamic requirements required by original equipment manufacturers (OEMs), has been to switch to shields made from nonwoven fabrics combined with PET (polyethylene teraphthalate) or polypropylene polymers. Although these materials are lightweight and effective at reducing sound attenuation, they are expensive costing two to three times as much as standard polymer shields.
Accordingly, there is a need to develop low cost materials, designs, and processing methods to produce products that are both lightweight and feature improved NVH properties.